HDR Brachytherapy for Intraocular Melanoma - Project Summary/Abstract The overall objective of this Phase I program is to develop a brachytherapy system for the treatment of intraocular melanoma that reduces hospitalization time, provides improved dosimetry to reduce complications, improves safety for the clinician and reduces cost. This will be achieved through the development of an improved high dose rate brachytherapy system based on the low- energy gamma ray source 169 Ytterbium. Such development would eliminate the long hospitalization required with the current low dose rate treatment and reduce the radiation exposure to the surgeon and other hospital personnel. This would also achieve the benefits of superior dose optimization with its collateral improvement in therapeutic response, along with potentially better treatment efficacy available with afterloaded high dose rate temporary brachytherapy sources. We further believe that the specific radiological properties of this radionuclide will result in reduced dose to the sclera than can be achieved with the currently-available radionuclides, and thereby will reduce the complications from this procedure. We aim to demonstrate that high dose rate brachytherapy using 169 Ytterbium can be an effective treatment method for this cancer. Choroidal melanoma is the most common primary ocular malignancy, with some 1500 new cases reported yearly in the United States. These tumors are both sight- and life-threatening, with approximately 10% to 30% five-year mortality rate owing to systemic metastasis, depending on tumor size. The National Eye Institute- and National Cancer Institute-sponsored Collaborative Ocular Melanoma Study (COMS), a prospective multicenter clinical trial to judge treatment efficacy brachytherapy v. enucleation in the context of mortality, showed that brachytherapy conveyed as good a survival rate as enucleation, in both a statistical and practical sense. However, current eye plaques, containing 125Iodine or 103Palladium brachytherapy seeds must be left in place from 5 to 12 days, and require a second surgery to remove the plaque from the patient. The low average photon emission energies from 125 Iodine and 103 Palladium result in a high dose to the sclera in order to deliver the desired dose to the apex of the tumor. This results in risk of damage and complications. The development of a high dose rate brachytherapy system using 169 Ytterbium can be practically and economically implemented and will overcome the shortcomings of the current treatment method while providing clinical benefit. HDR Brachytherapy for Intraocular Melanoma - Project Narrative The clinical implementation of high dose rate 169 Ytterbium brachytherapy will benefit patients by resulting in shorter treatment of certain types of eye cancer, and potentially fewer complications. This will also lead to greater safety to the physicians performing this procedure and greater comfort to the patients by reducing their hospital stay from a week to a day. It will also result in reduced cost for this procedure. [unreadable] [unreadable] [unreadable] [unreadable]